mortgage
(4)the term “mortgage” means a first mortgage on real estate in fee simple, or on the interest of either the lessor or lessee thereof (A) under a lease for not less than ninety-nine years which is renewable, or (B) under a lease having a period of not less than ten years to run beyond the maturity date of the mortgage. The term “first mortgage” means such classes of first liens as are commonly given to secure advances (including but not limited to advances during construction) on, or the unpaid purchase price of, real estate under the laws of the State in which the real estate is located, together with the credit instrument or instruments, if any, secured thereby, and any mortgage may be in the form of one or more trust mortgages or mortgage indentures or deeds of trust, securing notes, bonds, or other credit instruments, and, by the same instrument or by a separate instrument, may create a security interest in initial equipment, whether or not attached to the realty. The term “mortgagor” shall have the meaning set forth insection 1713(a) of this title;